Plane polygons revisited

A method used by electrical engineers to analyse polyphase alternating current systems suggests a generalisation to arbitrary plane polygons of a theorem on triangles nowadays known, for obscure reasons, as ‘Napoleon's Theorem': the centroids of equilateral triangles erected on the sides of an arbitrary triangle form the vertices of an equilateral triangle. The generalisation to other polygons uses a construction first studied by C.-A. Laisant in 1877; results of Jesse Douglas (1940) and the author (1941) are re-derived by means of the elementary algebra of finite-dimensional vector spaces over the field of complex numbers.

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Multi-variable quaternionic spectral analysis

Opuscula Mathematica ◽

10.7494/opmath.2021.41.3.335 ◽

2021 ◽

Vol 41 (3) ◽

pp. 335-379

Author(s):

Ilwoo Cho ◽

Palle E.T. Jorgensen

Keyword(s):

Spectral Analysis ◽

Functional Equations ◽

Linear Functional ◽

Vector Spaces ◽

Complex Numbers ◽

Dimensional Vector ◽

Finite Dimensional ◽

Linear Functional Equations ◽

Non Linear

In this paper, we consider finite dimensional vector spaces $\mathbb{H}^n$ over the ring $\mathbb{H}$ of all quaternions. In particular, we are interested in certain functions acting on $\mathbb{H}^n$, and corresponding functional equations. Our main results show that (i) all quaternions of $\mathbb{H}$ are classified by the spectra of their realizations under representation, (ii) all vectors of $\mathbb{H}^n$ are classified by a canonical extended setting of (i), and (iii) the usual spectral analysis on the matricial ring $M_n(\mathbb{C})$ of all $(n \times n)$-matrices over the complex numbers $\mathbb{C}$ has close connections with certain "non-linear" functional equations on $\mathbb{H}^n$ up to the classification of (ii).

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Neutrosophic Quadruple Vector Spaces and Their Properties

Mathematics ◽

10.3390/math7080758 ◽

2019 ◽

Vol 7 (8) ◽

pp. 758 ◽

Cited By ~ 1

Author(s):

Vasantha Kandasamy W.B. ◽

Ilanthenral Kandasamy ◽

Florentin Smarandache

Keyword(s):

Finite Field ◽

Final Section ◽

Vector Spaces ◽

Complex Numbers ◽

Dimensional Vector ◽

Characteristic P ◽

Finite Dimensional ◽

Classical Property ◽

First Time

In this paper authors for the first time introduce the concept of Neutrosophic Quadruple (NQ) vector spaces and Neutrosophic Quadruple linear algebras and study their properties. Most of the properties of vector spaces are true in case of Neutrosophic Quadruple vector spaces. Two vital observations are, all quadruple vector spaces are of dimension four, be it defined over the field of reals R or the field of complex numbers C or the finite field of characteristic p, Z p ; p a prime. Secondly all of them are distinct and none of them satisfy the classical property of finite dimensional vector spaces. So this problem is proposed as a conjecture in the final section.

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A closer look at the stable completion

10.23943/princeton/9780691161686.003.0005 ◽

2017 ◽

Author(s):

Ehud Hrushovski ◽

François Loeser

Keyword(s):

Inverse Limit ◽

Unit Vector ◽

Vector Spaces ◽

Dimensional Vector ◽

Compact Sets ◽

Linear Topology ◽

Topological Embedding ◽

Definable Set ◽

Finite Dimensional ◽

The One

This chapter introduces the concept of stable completion and provides a concrete representation of unit vector Mathematical Double-Struck Capital A superscript n in terms of spaces of semi-lattices, with particular emphasis on the frontier between the definable and the topological categories. It begins by constructing a topological embedding of unit vector Mathematical Double-Struck Capital A superscript n into the inverse limit of a system of spaces of semi-lattices L(Hsubscript d) endowed with the linear topology, where Hsubscript d are finite-dimensional vector spaces. The description is extended to the projective setting. The linear topology is then related to the one induced by the finite level morphism L(Hsubscript d). The chapter also considers the condition that if a definable set in L(Hsubscript d) is an intersection of relatively compact sets, then it is itself relatively compact.

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Orbit-Finite-Dimensional Vector Spaces and Weighted Register Automata

2021 36th Annual ACM/IEEE Symposium on Logic in Computer Science (LICS) ◽

10.1109/lics52264.2021.9470634 ◽

2021 ◽

Author(s):

Mikolaj Bojanczyk ◽

Bartek Klin ◽

Joshua Moerman

Keyword(s):

Vector Spaces ◽

Dimensional Vector ◽

Finite Dimensional

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A note on extensions of multilinear maps defined on multilinear varieties

Proceedings of the Edinburgh Mathematical Society ◽

10.1017/s0013091521000055 ◽

2021 ◽

pp. 1-26

Author(s):

W. T. Gowers ◽

L. Milićević

Keyword(s):

Finite Fields ◽

Vector Spaces ◽

Restriction Map ◽

Zero Set ◽

Dimensional Vector ◽

Prime Field ◽

Finite Dimensional ◽

Multilinear Maps ◽

Multilinear Map

Abstract Let $G_1, \ldots , G_k$ be finite-dimensional vector spaces over a prime field $\mathbb {F}_p$ . A multilinear variety of codimension at most $d$ is a subset of $G_1 \times \cdots \times G_k$ defined as the zero set of $d$ forms, each of which is multilinear on some subset of the coordinates. A map $\phi$ defined on a multilinear variety $B$ is multilinear if for each coordinate $c$ and all choices of $x_i \in G_i$ , $i\not =c$ , the restriction map $y \mapsto \phi (x_1, \ldots , x_{c-1}, y, x_{c+1}, \ldots , x_k)$ is linear where defined. In this note, we show that a multilinear map defined on a multilinear variety of codimension at most $d$ coincides on a multilinear variety of codimension $O_{k}(d^{O_{k}(1)})$ with a multilinear map defined on the whole of $G_1\times \cdots \times G_k$ . Additionally, in the case of general finite fields, we deduce similar (but slightly weaker) results.

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Topological equivalence and rigidity of flows on certain solvmanifolds

Ergodic Theory and Dynamical Systems ◽

10.1017/s0143385799130116 ◽

1999 ◽

Vol 19 (3) ◽

pp. 559-569

Author(s):

D. BENARDETE ◽

S. G. DANI

Keyword(s):

Lie Group ◽

Vector Spaces ◽

Complex Numbers ◽

Real Vector ◽

Orbit Equivalent ◽

Finite Dimensional ◽

Generic Class ◽

Induced Flow ◽

Simply Connected ◽

Solvable Lie Group

Given a Lie group $G$ and a lattice $\Gamma$ in $G$, a one-parameter subgroup $\phi$ of $G$ is said to be rigid if for any other one-parameter subgroup $\psi$, the flows induced by $\phi$ and $\psi$ on $\Gamma\backslash G$ (by right translations) are topologically orbit-equivalent only if they are affinely orbit-equivalent. It was previously known that if $G$ is a simply connected solvable Lie group such that all the eigenvalues of $\mathrm{Ad} (g) $, $g\in G$, are real, then all one-parameter subgroups of $G$ are rigid for any lattice in $G$. Here we consider a complementary case, in which the eigenvalues of $\mathrm{Ad} (g)$, $g\in G$, form the unit circle of complex numbers.Let $G$ be the semidirect product $N \rtimes M$, where $M$ and $N$ are finite-dimensional real vector spaces and where the action of $M$ on the normal subgroup $N$ is such that the center of $G$ is a lattice in $M$. We prove that there is a generic class of abelian lattices $\Gamma$ in $G$ such that any semisimple one-parameter subgroup $\phi$ (namely $\phi$ such that $\mathrm{Ad} (\phi_t)$ is diagonalizable over the complex numbers for all $t$) is rigid for $\Gamma$ (see Theorem 1.4). We also show that, on the other hand, there are fairly high-dimensional spaces of abelian lattices for which some semisimple $\phi$ are not rigid (see Corollary 4.3); further, there are non-rigid semisimple $\phi$ for which the induced flow is ergodic.

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